C#匿名委托实现递归，将所有部门根据上下级关系显示在一个列表中,用于展示到下拉框中

Posted 2021-10-15 棉晗榜

/// <summary>
/// 将所有部门根据上下级关系显示在一个列表中,用于展示到下拉框中
/// </summary>
/// <returns></returns>
public async Task<List<Department>> GetTreeDepartment()
{
    await Task.Yield();
    var listAll = GetAllDepartment();
    List<Department> tree = new List<Department>();

    //一级
    var list_01 = listAll.Where(x => string.IsNullOrWhiteSpace(x.Parent_id));

    Action<Department, List<Department>> func = null;
    func = (q, list) =>
    {
        //查找子集
        var child = listAll.Where(x => x.Parent_id == q.Id);

        //是否有子集,1=有，0=无
        q.E2=child?.Count()>0? "1":"0";

        list.Add(q);
        if (child != null && child.Count() > 0)
        {
            foreach (var item in child)
            {
                //计算层级
                item.E7 = q.E7 + 1;
                func(item, list);
            }
        }
    };

    foreach (var item in list_01)
    {
        //计算层级
        item.E7 = 1;
        func(item, tree);
    }
    return tree;
}
  

    /// <summary>
    /// 部门
    /// </summary>
    public class Department : BaseEntity
    {
        /// <summary>
        /// 主键
        /// </summary>
        [Key]
        public string Id { get; set; }

        /// <summary>
        /// 部门名称
        /// </summary>
        public string Department_name { get; set; }

        /// <summary>
        /// 父级id
        /// </summary>
        public string Parent_id { get; set; }

        /// <summary>
        /// 排序
        /// </summary>
        public int Sno { get; set; }

        /// <summary>
        /// 是否启用，1=启用，0=禁用
        /// </summary>
        public byte? State { get; set; }
    }

   /// <summary>
    /// 扩展字段
    /// </summary>
    public class BaseEntity
    {
        /// <summary>
        /// 扩展字段
        /// </summary>
        [NotMapped]
        public string E1 { get; set; }

        /// <summary>
        /// 扩展字段
        /// </summary>
        [NotMapped]
        public string E2 { get; set; }

        /// <summary>
        /// 扩展字段
        /// </summary>
        [NotMapped]
        public string E3 { get; set; }

        [NotMapped]
        public string E4 { get; set; }

        [NotMapped]
        public string E5 { get; set; }

        [NotMapped]
        public string E6 { get; set; }

        /// <summary>
        /// 扩展字段
        /// </summary>
        [NotMapped]
        public int E7 { get; set; }

        [NotMapped]
        public List<string> List1 { get; set; } = new List<string>();

    }